Managers of Seven-Eleven Japan Co.'s franchise shops sued the nation's biggest convenience store chain operator Tuesday for some ¥230 million in damages, saying they lost profits after being banned from selling food products close to their expiration dates at discount prices.

The lawsuit sheds light on where the power lies in the convenience-store industry. Some franchise managers say they have no choice but to obey orders from gigantic chain operators or risk having their contracts terminated.

The lawsuit, filed at the Tokyo High Court by Seven-Eleven store managers from Hokkaido, Chiba, Osaka, Hyogo and Okayama prefectures, came after the Fair Trade Commission issued a cease and desist order for enforcing the ban June 22.